Depressive symptom clusters and neuropsychological performance in mild Alzheimer's and cognitively normal elderly

Plasma Total Tau and Neurobehavioral Symptoms of Cognitive Decline in Cognitively Normal Older Adults

Depression and related neurobehavioral symptoms are common features of Alzheimer’s disease and other dementias. The presence of these potentially modifiable neurobehavioral symptoms in cognitively intact older adults may represent an early indication of pathophysiological processes in the brain. Tau pathology is a key feature of a number of dementias. A number of studies have found an association between tau and neurobehavioral symptoms. The current study investigated the relationship of a blood-based biomarker of tau and symptoms of depression, anxiety, worry, and sleep disturbances in 538 community based, cognitively normal older adults. Logistic regression revealed no significant relationship between plasma total tau and any measures of neurobehavioral symptoms. To assess the impact of level of tau on these relationships, participants were divided into those in the highest quintile of tau and those in the lower four quintiles. Regression analyses showed a significant relationship between level of plasma total tau and measures of depression, apathy, anxiety, worry and sleep. The presence of higher levels of plasma tau and elevated neurobehavioral symptoms may be an early indicator of cognitive decline and prodromal Alzheimer’s disease. Longitudinal research is needed to evaluate the impact of these factors on the development of dementia and may suggest areas for early intervention.

Weak associations between depressive symptom severity, depressive symptom clusters, and cognitive performance in young to middle-aged men without clinical depression

Evidence suggests different depressive symptoms are related to  specific aspects of cognition, especially in older adults. The current study extended this literature by examining depressive symptom severity, symptom clusters, and cognitive functioning in young-to-middle aged adults. A sample of 2,560 men (mean age = 38.12 ± 2.41 years) withvalid Minnesota Multiphasic Personality Inventories (MMPI) and completed cognitive measures was drawn from a Vietnam veterans study. Bootstrapped regressions examined relationships between cognitive performance, MMPI Depression  scores, and Harris-Lingoes depression subscales after covariate adjustments. Follow-up analyses investigated non-elevated and elevated depressive symptom groups. We found inverse relationships between specific subscales (Subjective Depression and Mental Dullness) and attentional control. No significant relationships were evident for total depressive symptoms or for the group analyses. Findings suggest weak associations between depressive symptoms and cognition in young to middle-aged men without clinical depression, which adds to the literature on inconsistent findings in depressive symptom-cognition relationships.

Cognitive Function in Heart Failure Is Associated With Nonsomatic Symptoms of Depression But Not Somatic Symptoms

BACKGROUND

Patients with heart failure (HF) have high rates of cognitive impairment and depressive symptoms. Depressive symptoms have been associated with greater cognitive impairments in HF; however, it is not known whether particular clusters of depressive symptoms are more detrimental to cognition than others.

OBJECTIVE

The aim of this study was to identify whether somatic and/or nonsomatic depressive symptom clusters were associated with cognitive function in persons with HF.

METHODS

Participants were 326 HF patients (40.5% women, 26.7% non-white race-ethnicity, aged 68.6 ± 9.7 years). Depressive symptoms were measured using a depression questionnaire commonly used in medical populations: the Patient Health Questionnaire-9. Somatic and nonsomatic subscale scores were created using previous factor analytic results. A neuropsychological battery tested attention, executive function, and memory. Composites were created using averages of age-adjusted scaled scores. Regressions adjusting for demographic and clinical factors were conducted.

RESULTS

Regressions revealed that Patient Health Questionnaire-9 total was associated with attention (β = -.14, P = .008) and executive function (β = -.17, P = .001). When analyzed separately, the nonsomatic subscale, but not the somatic symptoms subscale (P values ≥ .092), was associated with attention scores (β = -.15, P = .004) and memory (β = -.11, P = .044). Both nonsomatic (β = -.18, P < .001) and somatic (β = -.11, P = .048) symptoms were related to executive function. When included together, only the nonsomatic symptom cluster was associated with attention (β = -.15, P = .020) and executive function (β = -.19, P = .003).

CONCLUSIONS

Greater overall depressive symptom severity was associated with poorer performance on multiple cognitive domains, an effect driven primarily by the nonsomatic symptoms of depression.

CLINICAL IMPLICATIONS

These findings suggest that screening explicitly for nonsomatic depressive symptoms may be warranted and that the mechanisms underlying the depression-cognitive function relationship in HF are not solely related to sleep or appetite disturbance. Thus, interventions that target patients' somatic symptoms only (eg, poor appetite or fatigue) may not yield maximum cognitive benefit compared with a comprehensive treatment that targets depressed mood, anhedonia, and other nonsomatic symptoms.

Depressive Symptoms Affect Working Memory in Healthy Older Adult Hispanics

OBJECTIVES

Low and middle income nations will experience an unprecedented growth of the elderly population and subsequent increase in age-related neurological disorders. Worldwide prevalence and incidence of all-types of neurological disorders with serious mental health complications will increase with life expectancy across the globe. One-in- ten individuals over 75 has at least moderate cognitive impairment. Prevalence of cognitive impairment doubles every 5 years thereafter. Latin America's population of older adult's 65 years and older is growing rapidly, yet little is known about cognitive aging among healthy older Latinos. Clinically significant depressive symptomatology is common among community-dwelling older adults and is associated with deficits across multiple cognitive domains, however much of the literature has not modeled the unique effects of depression distinct from negative and low positive affect. Our objective was to understand how mental health affects cognitive health in healthy aging Latinos.

METHODS

The present study used confirmatory factor analysis (CFA) and structural equation modeling (SEM) to examine the relative effects of Negative Affect, Positive Affect and Geriatric Depression on Verbal Memory, Verbal Reasoning, Processing Speed, and Working Memory in healthy aging Latinos. Data was collected from a sample of healthy community dwelling older adults living in San Jose, Costa Rica. Modeling of latent variables attenuated error and improved measurement reliability of cognition, affect, and depression variables.

RESULTS

Costa Ricans enjoy a notoriety for being much happier than US citizens and are renowned as one of the happiest nations in the world in global surveys. This was born out in these data. Costa Rican affective profiles differed substantively from US profiles. Levels of negative affect and depression were similar to US samples, but their levels of positive affect were much higher. Cognitive performance of these Costa Rican older adults was similar to US-age and education matched peers. CFA and SEM found that increased depressive symptomatology had deleterious effects on Working Memory made up of subtest scores sampling simple attention and vigilance for numbers. Verbal Memory, Verbal Reasoning, and Processing Speed were not affected by self-reported Positive Affect, Negative Affect or Depressive symptoms.

CONCLUSION

Costa Rican older adults were happy, as evidenced by the high ratio of positive affect to relatively low negative affect. Thus, we were somewhat surprised to find that depressive symptoms were selectively correlated to decrements in working memory and that negative and positive affect contributed negligible amounts of variance to any of the cognitive factors. Because of the methodological rigor of latent variable analysis, these results are very specific. The Working Memory factor is not contaminated with Speed of Processing or other measured cognitive factors. Likewise, the measured Geriatric Depression represents symptoms that are richly cognitive, not overtly affective.

A depressive endophenotype of poorer cognition among cognitively healthy community-dwelling adults: results from the Western Australia memory study

OBJECTIVE

The objective was to evaluate in a cognitively normal population the utility of an endophenotype of the depression-cognition link previously shown to be related to cognitive functioning in mild cognitive impairment and Alzheimer's disease.

METHODS

The data of 460 cognitively normal adults aged 32-92 years (M = 63.5, standard deviation = 9.24) from the Western Australian Memory Study with the Cross-national comparisons of the Cambridge Cognitive Examination-revised (CAMCOG-R) scores and 30-item Geriatric Depression Scale (GDS) scores were analyzed to determine the relationship between the five-item depressive endophenotype (DepE) scale drawn from the GDS and level of performance on a measure of cognitive functioning.

RESULTS

For the entire sample, there was a nonsignificant trend toward a negative relationship between DepE and CAMCOG-R scores. When analyzed for those 65 years and older, there was a significant negative relationship between the two measures (p = 0.001) with DepE scores significantly increasing the risk for performing more poorly on the CAMCOG-R (odds ratio = 1.53). Analysis of data for those 70 years and older showed that DepE was the only predictor significantly related to poorer CAMCOG-R performance (p = 0.001). For the 70 years and older group, DepE scores significantly increased the risk of poorer CAMCOG-R scores (odds ratio = 2.23). Analysis of the entire sample on the basis of ApoEε4 carrier status revealed that DepE scores were significantly negatively related only to ApoEε4 noncarrier regardless of age.

CONCLUSIONS

Elevated DepE scores are associated with poor neuropsychological performance among cognitively normal older adults. Use of the DepE may allow for the identification of a subset of older adults where depression is a primary factor in cognitive decline and who may benefit from antidepressant therapies.

Impaired cognition in depression and Alzheimer (AD): a gradient from depression to depression in AD

Objective To assess cognition in major depressed (MD), Alzheimer's disease (AD), and depression in AD elderly. Method Subjects were evaluated by Mini Mental, Rey Auditory Verbal Learning Test, Rey Complex Figure, Digit Span, Similarities, Trail Making A/B, Verbal Fluency and Stroop. One-way ANOVA and multivariate models were used to compare the performance of each group on neuropsychological tests. Results We evaluated 212 subjects. Compared to MD, attention, working memory, processing speed and recall showed significantly better in controls. Controls showed significantly higher performance in all cognitive measures, except in attention compared to AD. Verbal fluency, memory, processing speed and abstract reasoning in MD was significantly higher compared to AD. AD was significantly better in general cognitive state than depression in AD. All other cognitive domains were similar. Conclusion A decreasing gradient in cognition appeared from the control to depression in AD, with MD and AD in an intermediate position.

A depressive endophenotype of mild cognitive impairment and Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is a devastating public health problem that affects over 5.4 million Americans. Depression increases the risk of Mild Cognitive Impairment (MCI) and AD. By understanding the influence of depression on cognition, the potential exists to identify subgroups of depressed elders at greater risk for cognitive decline and AD. The current study sought to: 1) clinically identify a sub group of geriatric patients who suffer from depression related cognitive impairment; 2) cross validate this depressive endophenotype of MCI/AD in an independent cohort.

METHODS AND FINDINGS

Data was analyzed from 519 participants of Project FRONTIER. Depression was assessed with the GDS30 and cognition was assessed using the EXIT 25 and RBANS. Five GDS items were used to create the Depressive endophenotype of MCI and AD (DepE). DepE was significantly negatively related to RBANS index scores of Immediate Memory (B=-2.22, SE=.37, p<0.001), visuospatial skills (B=-1.11, SE=0.26, p<0.001), Language (B=-1.03, SE=0.21, p<0.001), Attention (B=-2.56, SE=0.49, p<0.001), and Delayed Memory (B=-1.54, SE = 037, p<0.001), and higher DepE scores were related to poorer executive functioning (EXIT25; B=0.65, SE=0.19, p=0.001). DepE scores significantly increased risk for MCI diagnosis (odds ratio [OR] = 2.04; 95% CI=1.54-2.69). Data from 235 participants in the TARCC (Texas Alzheimer's Research & Care Consortium) were analyzed for cross-validation of findings in an independent cohort. The DepE was significantly related to poorer scores on all measures, and a significantly predicted of cognitive change over 12- and 24-months.

CONCLUSION

The current findings suggest that a depressive endophenotype of MCI and AD exists and can be clinically identified using the GDS-30. Higher scores increased risk for MCI and was cross-validated by predicting AD in the TARCC. A key purpose for the search for distinct subgroups of individuals at risk for AD and MCI is to identify novel treatment and preventative opportunities.

Risk factors for mild cognitive impairment among Mexican Americans

BACKGROUND

Although a great deal of literature has focused on risk factors for mild cognitive impairment (MCI), little published work examines risk for MCI among Mexican Americans.

METHODS

Data from 1628 participants (non-Hispanic n = 1002; Mexican American n = 626) were analyzed from two ongoing studies of cognitive aging and Alzheimer's disease, Project FRONTIER (Facing Rural Obstacles to health Now Through Intervention, Education & Research) and TARCC (Texas Alzheimer's Research & Care Consortium).

RESULTS

When looking at the full cohorts (non-Hispanic and Mexican American), age, education, Apolipoprotein E (APOE) ε4 status and gender were consistently related to MCI diagnosis across the two cohorts. However, when split by ethnicity, advancing age was the only significant risk factor for MCI among Mexican Americans across both cohorts.

CONCLUSIONS

The current data suggest that many of the previously established risk factors for MCI among non-Hispanic cohorts may not be predictive of MCI among Mexican Americans and point to the need for additional work aimed at understanding factors related to cognitive aging among this underserved segment of the population.

Serum folate and B12 levels in association with cognitive impairment among seniors: results from the VELESTINO study in Greece and meta-analysis

OBJECTIVE

To summarize existing evidence on the effect of serum folate and vitamin B12 levels on cognitive impairment among elders via a meta-analysis, also including unpublished data from a cross-sectional study of seniors ( > 65 years) residing in Velestino, Greece.

METHOD

Serum measurements and Mini-Mental State Examination (MMSE) assessments were available for 593 Velestinians. In addition, 12 studies availing data on folate blood levels (N = 9,747) and 9 on B12 (N = 8,122) were identified following a search algorithm; pooled effect estimates were derived.

RESULTS

Cognitive impairment (MMSE < 24) among Velestenians was associated with lower education level in both genders; decreased social activity, depressive symptoms and low folate levels in males; older age in females. Meta-analyses showed an adverse effect of low-folate levels on cognition (OR: 1.66, 95% CI: 1.40-1.96); B12 was nonsignificantly associated (OR: 1.11, 95% CI: 0.88-1.40).

DISCUSSION

Low folate levels are associated with cognitive impairment of seniors; underlying pathophysiological mechanisms should be further explored.

Characterization of Mexican Americans with mild cognitive impairment and Alzheimer's disease

The purpose of the study was to provide characterization of Mexican Americans who meet criteria for Alzheimer's disease (AD) and mild cognitive impairment (MCI). For the study, 1,069 participants ages 40 and above who self-identified as either non-Hispanic white (n = 633) or Mexican American (n = 436) were recruited using a community-based participatory research approach. Global cognition was assessed via the Mini-Mental State Examination (MMSE), dementia severity by the Clinical Dementia Rating Scale, and depression via the Geriatric Depression Scale 30-item version. Age, gender, education, ApoE ε4 allele frequency, and diabetic diagnoses were also analyzed. The findings showed that Mexican Americans (normal controls, MCI, and AD) were younger, less highly educated, performed more poorly on the MMSE, endorsed more symptoms of depression, were more likely to be diagnosed with diabetes, and possessed the ApoE ε4 allele less frequently. Age was the only significant risk factor for cognitive dysfunction (AD/MCI) among Mexican Americans (OR = 1.06, 95% CI = 1.03-1.09). Age (B = 0.07, std = 0.02, p < 0.001) and ApoE ε4 presence (B = 0.9, std = 0.4, p = 0.02) were significantly related to increased disease severity. Given the rapidly growing and aging Mexican American population, there is a substantial need for research into cognitive aging, MCI, and AD among this ethnic group. The current findings hold important implications for both clinic and research settings and point to additional research needs.

Depression and cognitive impairment in older adults

Late life depression (LLD) is a heterogeneous illness with high rates of treatment resistance. Cognitive impairment is common in the context of LLD, and LLD may be a prodromal symptom and/or potentially a risk factor for dementia. This manuscript reviews the most recent research into the cognitive deficits associated with LLD and risk of conversion to dementia in the context of LLD. We discuss potential moderators and mediators of cognitive deficits in LLD, including demographic and clinical variables, in addition to brain structure and function. Potential interventions for cognitive symptoms of LLD are reviewed. We conclude with a discussion of the broader implications of what is now known about LLD, and how this might be applied toward improved prognosis and models for effective treatment.